William simpkin



(No Model.) I

W. SIMPKIN.

BALANCED SLIDE AND CUT OFF VALVE. No. 401,384. Patented Apr. 16, 1889...

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UNITED STATES PATENT FFICE.'

WVILLIAM SIMPKIN, OF RICHMOND, VIRGINIA, ASSIGNOR TO THE RICHMOND LOCOHOTIVE AND MACHINE URKS, OF SAME PLACE.

BALANCED SLlDE AND CUT-OFF VALVE.

SPECIFICATION forming part of Letters Patent No. 401,384, dated April 16, 1889.

Application filed September 14, 1888. Serial No. 285,376. (No model.)

T 0 all whom it may concern:

Be it known that I, WVILLIAM SIMPKIN, a citizen of the United States, residing at Richmond, in the county of Henrico and State of Virginia, have invented certain new and useful Improvements in Balanced Slide and Out-01f Valves; and I do hereby declare the following to be afull, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to balanced slidevalves; and it consists of certain novel constructions, combinations, and arrangements of parts hereinafter fully described, and pointed out by the claims, whereby a combined main and cut-01f balanced valve of simple construction and easy adjustment is produced.

In the accompanying drawings, Figure 1 is a vertical centrzl section through a steam-cylinder and valve-chest containing my balanced valve. Fig. 2 is a transverse section through the valve and a portion of the cylinder.

The letter A in the drawings represents a valve-chest; A", a steam-cylinder; B, avalveseat; C, amain valve; D, a cut-off valve; E, a balance-plate, and F, a valve-chest cover.

The main valve 0 is provided with supplyports 0 c and an exhaust-port, 0 Its top surface, c serves as a valve-seat for the cut-off valve D, which is reduced at its middle and of uniform thickness at its end cut-off portions, and it reciprocates between the valve 0 and a pressure-plate, c, fastened to the said valve by means of screws 0 and resting upon side flanges, c, of the main valve, thus forming a steam-tight tunnel-like way for the cutoff valve. The pressure-plate c is provided on top with an annular rim, 0 which snugly fits into a pendent annular rim, 6, of a diaphragm, e, of the balance-plate E. The top portion of this balance-plate is planed off and bears against the inner surface of the valve chest cover F, which is also planed off and ground to fit steam-tight with the balanceplate. Steam is admitted through the aper tures c in the rim 6 into the space between the pressure-plate c and the diaphragm e of the balance-plate E, in order to keep the main valve upon its seat B and the balance-plate against the valve-chest cover F.

The friction between the combined main valve and balance-plate and the valve-seat B and valve-chest cover F is adjusted by a screw bolt, G, fastened permanently, as shown, or

otherwise suitably, to the pressure-plate c and passed throughthe diaphragm c and receiving upon its upper end a nut, g, which bears upon the upper surface of the diaphragm. By screwing the nut up or down on its screw-bolt G the friction of the combined main valve and balance-plate can be augmented or diminished at will. In order to prevent the balanceplate from leaving the valve-chest cover by means of its gravity when steam is shut off from the valve-chest, I interpose a spring, r", between the diaphragm e and pressure-plate 0 which by its tension effects a constant contact between the said parts.

In order to prevent the nut g from turning after adjustment, it is provided with a checkwasher, g*, which is held down upon the diaphragm by means of a shoulder, g", of the nut, and is prevented from turningbyadowel-pin, g, lodged in the washer and diaphragm,said washer being provided with a set-screw, g, which bears against the cylindrical portion of the nut in the washer, whereby, when said setscrew is drawn tight, the nut g is prevented from turning. Access to the nut g is provided by means of an aperture, c in the top portion of the balance-plate E and an aperture, f, in the valve chest cover. The aperture e is closed steam-tight by a screw-plug, 6 after the adjustment of the nut g is effected.

The valve 0 is provided withayoke, H, and valve-stem h, and the cut-off valve D is provided with a valve-stem, (1'. These valvestems are to be operated, as usual, by means of eccentrics on the main shaft of the steamengine.

When the nut g is to be adjusted, steam is admitted into the valve-chest and the balanceplate is pressed by said steam against the valve-chest cover, whereupon the plug 6 is removed and the nut g screwed down on the diaphragm until a slight hissing sound indicates that the joint between the balance-plate and valve-chest cover leaks, whereupon the nut g is carefully turned back until this sound ceases, which indicates that a steam-tight joint has been produced. The valve thus adjusted and balanced as nearly as practicable by the means before described can be used with a minimum of power, and very slight Wear will be experienced.

It will be seen that the steam in the valvechest has free admission between the main valve and balanceplate, and by its pressure causes a perfect and permanent contact at the steam-joints, while the adjusting-bolt G prevents unnecessary friction Without becoming loose by yielding to the lateral strains created between the main valve and balance-plate through the reciprocating motion of the former and the resistance of the latter.

By inclosing the nut g between the diaphragm e and plugged top portion of the balance-plate E steam is prevented from escaping between the nut and diaphragm and at the aperture f.

I claim 1. In combination with a valve-chest, A, having an opening, f,in its cover, the slide-valve 0, having supply and exhaust ports, rimmed pressure-plate c 0 balance-plate E, having aperture 6 closing-plug e diaphragm e, and rim 6, bolt Gr, nut g, spring g, and cut-off valve D, substantially as and for the purpose set forth.

2. The combination, with a valve-chest, A, of the described main slide-valve C, pressureplate 0 the balance-plate E, and the bolt- G, having spring g, the nut g, having shoulder 9 the Washer g having dowel-pin g and set- V screw 9 substantially as and for the purpose NM. SIMPKIN.

WVitnesses:

GEO. J. ROGERS, ROGER B. ATKINSON. 

